Refrigeration



Feb. 9, 1932. F. D. PELTIER 1,844,677

, REFRIGERATION Filed May 19, 1931 2 Sheets-Sheet 1 Feb. 9, 1932. F. D. PELTIER 1,844,677

REFRIGERATION Filed May 19, 1951 2 Sheets-Sheet 2 INVENTOR. M,9%w

I ATTORNEY 5 carbon dioxide.

Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE FRANK D. PEL'IIER, OF EVAIN'BVILLE, INDIANA, ASSIGNOR TO SERVEL, 1110., 01

NEW YORK, N. Y., A CORPORATION OF DELAWARE REFRIGERATION Application filed Kay 19,

This invention relates to refrigeration and more specifically to a secondary cooling system the condensing portion of whlch 1s cooled by the transfer of heat to sublimate SOlld An outstanding disadvantage of the use of solid carbon dioxide, commonly known as dry ice, as a refrigerant'is the difficulty of controlling refrigeration. An ob ect of th1s 1 invention 1s to provide for transferring heat from. the medium to be cooled to a body of dry ice through a secondary cooling system, which latter is readily controlled. It is a further object of this invention to increase the'efliciency of such an arrangement by utilizing to its greatest extent the cooling capacity of the carbon dioxlde vapor resulting from the sublimation of the dry me.

Other objects and advantages will be apparent from the following description taken in connection with the accompanymg drawings, in which Fig. 1 is a side elevation partly broken away showing apparatus contemplated by this invention;

Fig. 2, a top view of the arrangement shown in Fi 1;

Fig. 3, a section on line 33 of Fig. 1;

Fig. 4, a section taken on line 44 of Fig. 2; and

Fig. 5, a diagrammatic View of apparatus contemplated by this invention.

One well known application of dry me as a refrigerant is in trucks for transporting and delivering frozen food products and the like, wherefore this invention is described in connection with one form of apparatus particularly adaptable to such trucks. Referring to the drawings, in which like reference numerals indicate like parts, there is shown in Fig. 1 a metal container 10 adapted to receive a quantity of dry ice. Access to the container is through a chute 11 which may open through the roof of a truck and is closed, except when loading the dry ice, by a hatch, not shown. Around the outside of the metal container 10 in thermal contact therewith is placed the condenser coil 12 of a secondary cooling system. The container and the con- 1981. Serial No. 588,461.

denser coil are surrounded by heat insulating material which may comprise cork board 13 with the spaces filled With'hydrolene or some similar substance and the whole is enclosed in an outer casing 14.

Mounted on the outside of casing 14 is a heat exchanger 16 comprising an inner pipe 17 and an outer concentric pipe 18 between which there is an annular space 19. The pipes are coiled to conserve space, as illustrated. The annular space 19 in the heat exchanger is closed at each end by means of reducing sleeves 20. and 21. The reducing sleeve 20 is secured to the side of the chute 11 and the sleeve 21 may be secured in any manner such that a small port 22 which opens into one end of the annular space 19 between the heat exchanger tubes is open to atmosphere, for instance through the top of the truck. The other end of the annular space 19 communicates with the interior of the metal container 10 through a port 23 in the reducing sleeve 20 and the side of the chute 11, as shown in Figs. 1 and 2. The inner coil 17 of the heat exchanger 16 is con nected at one end to the upper end of the condenser coil 12. The other ends of the condenser coil 12 and the heat exchanger coil 17 are adapted to be connected respectively to the liquid inlet and vapor outlet of an evaporator 24 which may be of any desired design.

As shown in Fig. 5 the condenser coil 12, heat exchanger coil 17, and evaporator 24 constitute a secondary cooling system which may contain any desired refrigerating fluid. 85 Solid carbon dioxide in the container 10 is vaporized by heat absorbed from the secondary refrigerating fluid in the condenser coil 12 and the carbon dioxide vapor fills the container 10 and passes through the annular space 19 of the heat exchanger 16 to atmosphere through the opening 22.

Heat is absorbed from the medium to be cooled to vaporize the secondary liquid refrigerant in evaporator 24 and vapor passes 95 from the evaporator throughcoil 17 of the heat exchanger 16 where it is cooled by heat transfer to the carbon dioxide vapor in the annular space 19. The secondary refrigerant vapor then passes to the condenser coil 12 1M where it is liquefied by the transfer of heat to the solid carbon dioxide. Liquid refrigerant from the condenser coil returns to the evaporator 24 preferably through a control valve 25 which may be operated responsive to pressure or temperatures in any manner well known in the art.

It has been found advantageous to malntain a suflicient quantity of non-freezing solution in the container 10 for the conduction of heat from the condenser coil to the solid carbon dioxide. The carbon dioxide gas filling the container 1) acts as a heat insulator and the limited contact between the dry ice and the bottom of the metal container may not be suflicient for the necessary heat transfer.

It will be obvious to those skilled in the art that various other changes may be made in the construction and arrangement without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

I claim:

1. Refrigerating apparatus comprising a closed metal container for dry ice having a charging opening, a condenser coil around the outside of said container in thermal exchange relation therewith, heat insulating'material surrounding said container and ,coil, a casing around said insulating material, a heat exchanger comprising a pair of coiled concentric tubes, a conduit including the outer tube of the heat exchanger from said contamer to atmosphere, and an evaporator, said evaporator, condenser coil, and the inner tube of said heat exchanger being connected in series to form a fluid tight circuit.

2. Refrigerating apparatus comprising a fluid tight metal container, a condenser COIl in thermal exchange relation with said container, heat insulating material surrounding said container and coil. a heat exchanger, a conduit including one element of the heat exchanger from said container to atmosphere, and an evaporator, said evaporator. condenser coil, and the other element of said heat exchanger being connected in series to form a fluid tight circuit.

' 3. Refrigerating apparatus comprising a closed container for dry ice, a secondary cooling system having its condensing portion in thermal exchange relation with said container, a heat exchanger having one element in said secondary cooling system, and a conduit including the other element of said heat exchanger from said container to atmoshere.

4. Refrigerating apparatus comprising a closed container, a condenser in thermal exchange relation with said container, a heat exchanger, a conduit including one element of said heat exchanger communicating with said container, and an evaporator, said evaporator, condenser, and the other element of said heat exchanger being connected in series to form a fluid tight circuit.

5. Refrigerating apparatus comprising a closed container for dry ice, a condenser in thermal exchange relation with said container, a heat exchanger, a conduit including one element of the heat exchanger communicating with said container, an evaporator, said evaporator, condenser, and the other element of the heat exchanger being connected in series to form a fluid tight circuit, and a refrigerating fluid in said circuit.

6. Refrigerating apparatus comprising a closed metal container for dry ice, a nonfreezing heat-conducting liquid in said container, a condenser in thermal exchange relation with said liquid, heat insulating material surrounding said container and condenser, a heat exchanger, a conduit including one ele mentof the heat exchanger from said container to atmosphere, an evaporator, said evaporator, condenser, and the other element of said heat exchanger being connected in series to form a fluid tight circuit, and a volatile fluid in said circuit.

7. Refrigerating apparatus comprising a closed container for dry ice having a restricted gas outlet, a non-freezing heat-conducting liquid in said container, and a secondary cooling system having its condensing portion in thermal exchange relation with said liquid.

8. The method of refrigerating which comprises removing heat from a medium to be cooled to vaporize a liquid refrigerant, condensing the refrigerant by transferring heat to a quantity of non-freezing liquid, removing heat from said liquid to vaporize solid carbon dioxide, and conducting the resulting carbon dioxide gas in thermal exchange relation with the refrigerant Vapor.

9. -The method of refrigerating which comprises removing'heat tfrom a medium to be cooled to vaporize a liquid refrigerant, condensing the refrigerant by transferring heat to a quantity of non-freezing liquid, and re-- moving heat from said liquid to vaporize solid carbon dioxide.

In testimony whereof I affix my signature.

FRANK D. PELTIER. 

